Autometer 6871 tach

rallye bob · 05-23-2009, 06:46 AM

Who is running an Autometer "Ultimate Playback" tach?
I have a wiring question about the blue wire...

rodrocket · 05-23-2009, 07:21 AM

the Blue wire is for the trigger

have a look here this may help you

http://www.autometer.com/productPDF/0887F.pdf

regards
rod

rallye bob · 05-23-2009, 07:45 AM

Thanks Rod;
The instructions state....... NOTE: Playback tachs, and Playback boxes must have 12 volts applied to the blue wire. Recording will begin when 12 volts is removed......

So if I run the blue wire from, 12 v source through a n/o momentary switch, and then to tach.... I hit the momentary switch just before I leave, and the tach starts recording?
This tells me that the "blue" wire only has to see 12 v for an instant.... Is this true?
As you can tell, I'm not much for understanding auto wiring, and I need lots of help simplifying it... :-(
TIA

Rob Petrie E395 · 05-23-2009, 12:18 PM

These tachs are really made to be wired into the transbrake solonoid so when its released and the 12 volts goes away the tach starts recording beyond the 10 seconds that is already being held in memory so you can get 10 seconds before the run and the auctual run. I tried to figure out a way to put a momentary switch on the throttle linkage of my footbrake car and never found a good way to do it. I ended up putting button on the steering wheel and as soon as the other guy prestages I hit it and stageto give the tach the momentary 12 volts it need to start recording. The bad part of doing it this way is, first its one more thing to do when staging the car and second if the track doesnt have autostart and the other guy takes forever to stage or tries to burn you down it wont record the whole run due to the limit on how long it will record the run. If anybody has a good way to put a monemtary switch on the throttle linkage I would hear about it. At first I tried a NOS microswitch on the throttle body thinking when I went wide open at launch it would trigger the tach but the tach needs to see 12 volts and then starts recording when the 12 volts goes away so that did not work. I tried a couple of other ways but never came up with something I felt was safe and consistant. Again if anybody has something that works and would be willing to share there idea I would like to hear about it.

George Mirza · 05-23-2009, 08:49 PM

I have an LTM and I have the blue wire triggered by the brake light switch. The blue wire picks up power from the brake light side of the brake light switch, then it goes through a toggle switch on the dash and then to the LTM. When I have stagged I flip the switch on (energizing the blue wire) and when I release the brake pedal it breaks the circuit to the LTM and it starts recording. Works good, but it dosen't record the burnout or staging rpm, but it does start recording before the converter flashes, so you can see the stall speed. Like the other guys stated, they are ment to work with a trans brake.

Ed Carpenter · 05-23-2009, 08:57 PM

Dealt with this last weekend in Houston. Kevin Helms had me wire it straight to the line lock. Worked perfect after that. ED

rallye bob · 05-24-2009, 07:30 AM

Quote:

Originally Posted by deuces wild

Dealt with this last weekend in Houston. Kevin Helms had me wire it straight to the line lock. Worked perfect after that. ED

ED;
Can you diagram your "blue wire" hook up for me?
Just to clarify....... I use my line lock for burn outs only. No trans brake. Foot brake only.

Jeff Stout · 05-26-2009, 10:04 AM

Line lock button for me. It does record end of burnout and staging car, but has had enough time left over for recording to get entire run. I think 90 seconds total.

Dave Turner · 05-26-2009, 12:10 PM

Excellent timing, I was just about to post a similar thread.

Tim Lisson · 05-26-2009, 02:40 PM

Rallye Bob-

Another way, use a brake line pressure switch connected inline of your braking system with a TEE, they are two wire, begin with a 12 volt switch in the car to power wire once you prestage, arrow down /enter/enter on the tach, and leave. Removing your foot from the brake pedal will start the recording plus three seconds and you'll be set. If you decide to use a two step you can utilize the same circuit, however you would have to remember to shut the 12 volt switch off in the car to prevent the two step from energizing through the traps while braking, or install a long arm switch to interupt for hi gear.

Tim

05-23-2009, 06:46 AM	#1
rallye bob Member Join Date: Sep 2006 Location: Genoa, Illinois Posts: 489 Likes: 9 Liked 6 Times in 4 Posts	Autometer 6871 tach Who is running an Autometer "Ultimate Playback" tach? I have a wiring question about the blue wire...

05-23-2009, 07:21 AM	#2
rodrocket Junior Member Join Date: Sep 2008 Posts: 37 Likes: 1 Liked 0 Times in 0 Posts	Re: Autometer 6871 tach the Blue wire is for the trigger have a look here this may help you http://www.autometer.com/productPDF/0887F.pdf regards rod

05-23-2009, 07:45 AM	#3
rallye bob Member Join Date: Sep 2006 Location: Genoa, Illinois Posts: 489 Likes: 9 Liked 6 Times in 4 Posts	Re: Autometer 6871 tach Thanks Rod; The instructions state....... NOTE: Playback tachs, and Playback boxes must have 12 volts applied to the blue wire. Recording will begin when 12 volts is removed...... So if I run the blue wire from, 12 v source through a n/o momentary switch, and then to tach.... I hit the momentary switch just before I leave, and the tach starts recording? This tells me that the "blue" wire only has to see 12 v for an instant.... Is this true? As you can tell, I'm not much for understanding auto wiring, and I need lots of help simplifying it... :-( TIA

05-23-2009, 12:18 PM	#4
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,092 Likes: 162 Liked 216 Times in 77 Posts	Re: Autometer 6871 tach These tachs are really made to be wired into the transbrake solonoid so when its released and the 12 volts goes away the tach starts recording beyond the 10 seconds that is already being held in memory so you can get 10 seconds before the run and the auctual run. I tried to figure out a way to put a momentary switch on the throttle linkage of my footbrake car and never found a good way to do it. I ended up putting button on the steering wheel and as soon as the other guy prestages I hit it and stageto give the tach the momentary 12 volts it need to start recording. The bad part of doing it this way is, first its one more thing to do when staging the car and second if the track doesnt have autostart and the other guy takes forever to stage or tries to burn you down it wont record the whole run due to the limit on how long it will record the run. If anybody has a good way to put a monemtary switch on the throttle linkage I would hear about it. At first I tried a NOS microswitch on the throttle body thinking when I went wide open at launch it would trigger the tach but the tach needs to see 12 volts and then starts recording when the 12 volts goes away so that did not work. I tried a couple of other ways but never came up with something I felt was safe and consistant. Again if anybody has something that works and would be willing to share there idea I would like to hear about it.

05-23-2009, 08:49 PM	#5
George Mirza Senior Member Join Date: Jan 2002 Location: North Attleborough Ma. Posts: 522 Likes: 0 Liked 0 Times in 0 Posts	Re: Autometer 6871 tach I have an LTM and I have the blue wire triggered by the brake light switch. The blue wire picks up power from the brake light side of the brake light switch, then it goes through a toggle switch on the dash and then to the LTM. When I have stagged I flip the switch on (energizing the blue wire) and when I release the brake pedal it breaks the circuit to the LTM and it starts recording. Works good, but it dosen't record the burnout or staging rpm, but it does start recording before the converter flashes, so you can see the stall speed. Like the other guys stated, they are ment to work with a trans brake.

05-23-2009, 08:57 PM	#6
Ed Carpenter Live Reporter Join Date: May 2006 Location: Dripping Springs, Tx Posts: 2,709 Likes: 186 Liked 520 Times in 132 Posts	Re: Autometer 6871 tach Dealt with this last weekend in Houston. Kevin Helms had me wire it straight to the line lock. Worked perfect after that. ED __________________ Ed Carpenter 2005 Chevy Cobalt A/SM Race Engine Development

05-26-2009, 10:04 AM	#8
Jeff Stout VIP Member Join Date: Dec 2001 Location: phoenix Posts: 1,486 Likes: 66 Liked 704 Times in 281 Posts	Re: Autometer 6871 tach Line lock button for me. It does record end of burnout and staging car, but has had enough time left over for recording to get entire run. I think 90 seconds total.

05-26-2009, 12:10 PM	#9
Dave Turner VIP Member Join Date: Oct 2005 Location: Schomberg, ON, Canada Posts: 1,222 Likes: 1,606 Liked 364 Times in 138 Posts	Re: Autometer 6871 tach Excellent timing, I was just about to post a similar thread. __________________ Dave Turner SS/GT #1153

05-26-2009, 02:40 PM	#10
Tim Lisson Member Join Date: Aug 2003 Location: Solon Springs, WI Posts: 166 Likes: 0 Liked 0 Times in 0 Posts	Re: Autometer 6871 tach Rallye Bob- Another way, use a brake line pressure switch connected inline of your braking system with a TEE, they are two wire, begin with a 12 volt switch in the car to power wire once you prestage, arrow down /enter/enter on the tach, and leave. Removing your foot from the brake pedal will start the recording plus three seconds and you'll be set. If you decide to use a two step you can utilize the same circuit, however you would have to remember to shut the 12 volt switch off in the car to prevent the two step from energizing through the traps while braking, or install a long arm switch to interupt for hi gear. Tim